The HuffPo's comments system is also one of the worst on the web. Not only is the window for comments tiny, the length of comments is restricted to 350 words "by popular demand", but it does not allow for any HTML markup -- not even bolding or italicization.

It also tends to hang or throw server errors, leaving the user not knowing whether the comment is posted.

Logins also time out after a rather short period of time, meaning that if you take a fair amount of time to compose a decently thought out and referenced comment, you run the risk of losing it completely, since the system does not give any warning and just tosses the comment into the bit bucket.

The best comment system being used is probably on comedian and writer Adam Felber's blog,http://fanaticalapathy.com.